Question

find the polar coordinates of (-5,5) for which r > 0 and 0 is less than or equal to theta < 2pi. leave answers in radians.

Answer 1

use pythagorean theorem to find r

\[r=\sqrt{5^2+(-5)^2}\]

Answer 2

then theta is

Theta = sin^-1 (x/r)

Answer 3

or inverse sine

Answer 4

make sure ur calculator is in radians

Answer 5

also since x and y are equal, you know the angle is 45 degrees, or pi/2 radians

Answer 6

ok, I got (0, 7pi/4)
is that correct?

Answer 7

my prof gave us the eqn: tan theta= y/x to solve for theta